title: Multigate Doppler measurements of ultrasonic attenuation and blood hematocrit in human arteries.
abstract: A clinically applicable method for noninvasive measurement of hematocrit based on 20 MHz multigate Doppler ultrasound was developed. The ultrasound attenuation coefficient in blood is obtained by measuring the power of the signal coming from gates at different depths. A robust averaging method is introduced, which provides stable and repeatable results by using the echo signals from all depths inside the vessel. In vitro measurements have been done on porcine blood with hematocrit ranging from 3.0% to 65.0%. Steady and pulsatile flow conditions have been simulated using a peristaltic pump. The attenuation coefficient indicated the linear relation to hematocrit. The resulting correlation coefficient was R = 0.999 for the continuous blood flow and R = 0.992 for pulsatile flow. In vivo measurements have been performed in the brachial artery in 43 patients with hematocrit in the range of 32.0% to 49.3%. The mean absolute error has been 3.24% with a standard deviation of 3.72%.
authors.affiliation: Department of Ultrasound, Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland. wsecom@ippt.gov.pl
authors.forename: Wojciech
authors.initials: W
authors.lastname: Secomski
authors.forename: Andrzej
authors.initials: A
authors.lastname: Nowicki
authors.forename: Piero
authors.initials: P
authors.lastname: Tortoli
authors.forename: Robert
authors.initials: R
authors.lastname: Olszewski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000818:Animals; D001916:Brachial Artery / Q000000981:diagnostic imaging*; D003327:Coronary Disease / Q000000981:diagnostic imaging; D005260:Female; D006400:Hematocrit / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013552:Swine; D018617:Ultrasonography, Doppler, Pulsed / Q000379:methods*; D055815:Young Adult